Hey all, so I’ve been throwing this idea around in my head for a while now and I wanted to ask some of the gurus out there for your advice/opinion. I’m relatively new to the modding world, but have been around flashlights and lion batteries for a while now.
Anyway. I want to mod some cheap 3AA lanterns with some higher powered warmer LEDs for backpacking. Doesn’t have to be super powerful, just want about 100 lumens or so for 3-4hrs. Here are my thoughts:
I want to use this:
And drop in a warm or neutral white LED into it such as this:
I’ve done some searching about modding lanterns and got a few good hits but nothing that really addresses what i’m looking for. My questions are:
1) Can I just rip out the LEDs that are currently in the light and use the same wires to wire up the LED star?
2) Do I need a pill and driver for this LED (super n00b question I know)?
3) Will 3AA’s give enough power to the LED?
4) Do I need optics (I really just want a lot of flood)?
5) Will this blow up in my hands?
2) if you want decent runtime out of 3x AA I’d recommend a single mode 350mA AMC7135 driver like this from Kaidomain or something similar. You’ll also need to mount the LED to a piece of aluminium to dissipate the heat.
3) should be ok at low drive current, hopefully others will chime in
4) I would go for something to diffuse the light instead (translucent plastic of some sort) as bare LEDs are very glarey and by diffusing it you’ll make it look “bigger”
5) unlikely, it hasn’t killed me yet and I’m a prime candidate for stuff blowing up in my hands!
Here’s the lantern I modded out of a Coleman 4D lantern, soon to get a Nichia 219 in it (to replace the yucky XP-G cool white):
not quite what you’re after as I only really go car camping and it’d be too big for back packing, but you get the idea
1) maybe (depends on how they’re wired), but I wouldn’t. (probably tiny wires. voltage could be different. probably uses resistor to limit current, ie that wastes power, and power decreases as batteries drain).
1. It depends, you would have to measure the voltage that is being put out by the electronics. Most likely yes, but the LED will be brighter than you need.
2. You definitely need a pill, or a chunk of aluminum to attach the LED to. Whether or not you need a driver depends on the voltage. Most likely you would want to use a driver, a single 7135 chip could do this.
3. Yes, 3 AAs will give plenty of power for this. If you are willing to use li-ion batteries they will give more power for the space though. (If you could fit 2 18650s)
4. You certainly don't need them.
5. It's pretty damn hard to get an alkaline AA to blow up, I've tried. ;)
1) How big/thick of a heatsink do I need to attach the LED star to, will any piece of solid aluminum or copper work?
2) What gauge wires do you normally use or would be best for this particular set up?
3) Am I using a good enough LED star, is there something out there that is more efficient/better for my application?
I sure don't know it all, but here is an attempt to answer your questions:
1)not just like that: 5mm leds as the ones in your lantern (I looked it up on the dx-site, 11 or 15 of them) are usually very simply powered direct drive with a resistor to limit the current. High current leds as the one you want to put in can not be driven like that, so you will need better driver circuitry, you can find them cheap on dx as well, look for a driver with 3-4.5V input, and say 500-700mA output (for 100 lumens).
2) yes you do need some heatsinking, even at 500mA, so why not a pill, so that you can have the driver in it as well. I think the pill should even be in contact with some more aluminium to get rid of the heat well enough. Maybe better is to make an aluminium plate as a sort of ceiling above the 'aquarium' and screw the led-star directly onto that to spread out the heat. And perhaps some holes in the plastic above the ceiling to let the heat out.
3) 3AA's in series give 3-4.5V, that's ok, look for a suitable driver for that.
4) the light looks to have some light spreading (aquarium-like ) so if that is what you want, it should be ok I suppose.
5) if the led has some heatsinking, and using a moderate amount of current (like 500-700mA) it should be fine
Note: in your picture the led colour appears to be more like cool white than warm white
Note #2: dx sells camping lanterns with a high current Cree already (like this one). It is easier to mod one of those...
Hey thanks for your input! That is a good point. I’m wondering if there is even enough space in the unit to include a pill/heatsink in the “roof” of it.
Do you think something like these would be easier to work with, where the LED is in the base?
Haha, but of course. At the end of the day thats the most important criteria.
So am I correct in thinking that the things I will need, in order from top to bottom, would probably be:
- LED emitter on star
- Heat sink
Driver
How do I wire the driver up to the battery carrier? I’m assuming that two wires go from the driver to the LED, then another separate two go from the driver to the battery carrier?
a typical flashlight driver is round with one side with components on it and two wires (on most drivers they are already attached) coming out that go to the led. The other side just has two circular contact plates, the middle one goes to the + of the battery, the ring around it to the - of the battery, they are easy to solder a wire to.
I’d add some wire to that list. silicone or teflon insulation if you’re fancy…
as far as your wiring, yes that’s correct.
heatsinking - an xm-l at 350ma doesn’t need much…a piece of aluminum or copper will work…but the better your heatsink works, the brighter the led will stay (it will get dimmer as it gets hotter).
if i were using higher power, I’d go w/ the first lantern you linked, and one of the finned heatsinks I linked sticking out of the top, so that it is exposed to air.
optics - scotch tape on the inside of the ‘globe’ part of the lantern if you find there are overly bright spots…
Ah that also is a good idea, I might have to get both lanterns and play around with what works best.
As for optics/tape, I have some press ’n seal on my other lantern that works wonders for smoothening out the beam and also protecting the plastic from scratches.
Ok, cool. So if I wanted to use this driver from FastTech, the outer ring would go to the “NEG” end and the inner ring would be soldered with a wire to the “POS” end correct?
) so if that is what you want, it should be ok I suppose.
!